How does dune grass change a sand dune?

Sand dunes are formed on the coast when waves carry sand onto the shoreline and the wind blows it into drifts. The sand gets trapped on plants such as Sand Couch and Marram Grass and the embryo dunes start to grow. Marram Grass is one of the most important dune plants. It has long roots that grow down deeply in search of water. These roots help to hold the dunes together.
Further inland the dunes are more stable and have lots of different plants, mosses and lichens growing on them. There can even be a very wet area. This is known as the 'dune slack' and rushes and reeds that like lots of water will grow here.

Sand dunes are a very important habitat. They are also a popular place for people to visit. However they are very fragile environment and changes can take place quickly. To protect the dunes plants from being trampled too much, special wooden paths called 'boardwalks' are put down for people to walk on.